6,392 research outputs found
The SA-2239/WLQ-4(V) Cutty Sark distribution system
A redundant frequency and time distribution system provides a multiplicity of isolated outputs, all of which are derived from three atomic frequency standards. The distribution system monitors input parameters of the signals coming from the Cesium Standards and selects one to be the primary standard, phase locks an internal oscillator which has excellent aging characteristics in the open loop mode and acts as a filter to provide phase noise improvement, and generates 1 megahertz and 100 kHz by direct synthesis. Additionally, the system distributes RF and timing signals consisting of 5 MHz, 1 MHz, 100 kHz, BCD Time-of-Day, 1 pps and 1 ppm
The CosmicWatch Desktop Muon Detector: a self-contained, pocket sized particle detector
The CosmicWatch Desktop Muon Detector is a self-contained, hand-held cosmic
ray muon detector that is valuable for astro/particle physics research
applications and outreach. The material cost of each detector is under $100 and
it takes a novice student approximately four hours to build their first
detector. The detectors are powered via a USB connection and the data can
either be recorded directly to a computer or to a microSD card. Arduino- and
Python-based software is provided to operate the detector and an online
application to plot the data in real-time. In this paper, we describe the
various design features, evaluate the performance, and illustrate the detectors
capabilities by providing several example measurements.Comment: 11 pages, 8 figure
HSCO and DSCO: a multi-technique approach in the laboratory for the spectroscopy of interstellar ions
Protonated molecular species have been proven to be abundant in the
interstellar gas. This class of molecules is also pivotal for the determination
of important physical parameters for the ISM evolution (e.g. gas ionisation
fraction) or as tracers of non-polar, hence not directly observable, species.
The identification of these molecular species through radioastronomical
observations is directly linked to a precise laboratory spectral
characterisation. The goal of the present work is to extend the laboratory
measurements of the pure rotational spectrum of the ground electronic state of
protonated carbonyl sulfide (HSCO) and its deuterium substituted isotopomer
(DSCO). At the same time, we show how implementing different laboratory
techniques allows the determination of different spectroscopical properties of
asymmetric-top protonated species. Three different high-resolution experiments
were involved to detected for the first time the type rotational spectrum
of HSCO, and to extend, well into the sub-millimeter region, the type
spectrum of the same molecular species and DSCO. The electronic
ground-state of both ions have been investigated in the 273-405 GHz frequency
range, allowing the detection of 60 and 50 new rotational transitions for
HSCO and DSCO, respectively. The combination of our new measurements
with the three rotational transitions previously observed in the microwave
region permits the rest frequencies of the astronomically most relevant
transitions to be predicted to better than 100 kHz for both HSCO and
DSCO up to 500 GHz, equivalent to better than 60 m/s in terms of equivalent
radial velocity. The present work illustrates the importance of using different
laboratory techniques to spectroscopically characterise a protonated species at
high frequency, and how a similar approach can be adopted when dealing with
reactive species.Comment: 7 pages, 4 figures. Accepted for publication in Astronomy and
Astrophysic
Electrical and electronic devices and components: A compilation
Components and techniques which may be useful in the electronics industry are described. Topics discussed include transducer technology, printed-circuit technology, solid state devices, MOS transistors, Gunn device, microwave antennas, and position indicators
Low-power dual-rail multiple-valued current-mode logic circuit using multiple input-signal levels
科研費報告書収録論文(課題番号:12480064・基盤研究(B)(2) ・H12~H14/研究代表者:亀山, 充隆/配線ボトルネックフリー2線式多値ディジタルコンピューティングVLSIシステム
A new photon recoil experiment: towards a determination of the fine structure constant
We report on progress towards a measurement of the fine structure constant to
an accuracy of or better by measuring the ratio of the
Planck constant to the mass of the cesium atom. Compared to similar
experiments, ours is improved in three significant ways: (i) simultaneous
conjugate interferometers, (ii) multi-photon Bragg diffraction between same
internal states, and (iii) an about 1000 fold reduction of laser phase noise to
-138 dBc/Hz. Combining that with a new method to simultaneously stabilize the
phases of four frequencies, we achieve 0.2 mrad effective phase noise at the
location of the atoms. In addition, we use active stabilization to suppress
systematic effects due to beam misalignment.Comment: 12 pages, 9 figure
One way Doppler extractor. Volume 1: Vernier technique
A feasibility analysis, trade-offs, and implementation for a One Way Doppler Extraction system are discussed. A Doppler error analysis shows that quantization error is a primary source of Doppler measurement error. Several competing extraction techniques are compared and a Vernier technique is developed which obtains high Doppler resolution with low speed logic. Parameter trade-offs and sensitivities for the Vernier technique are analyzed, leading to a hardware design configuration. A detailed design, operation, and performance evaluation of the resulting breadboard model is presented which verifies the theoretical performance predictions. Performance tests have verified that the breadboard is capable of extracting Doppler, on an S-band signal, to an accuracy of less than 0.02 Hertz for a one second averaging period. This corresponds to a range rate error of no more than 3 millimeters per second
Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
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